A rear axle gear is intended to distribute the driving torque to each of a vehicle's tractive wheels by means of a pinion and a crownwheel. The diameter of the pinion largely determines the width of the rear axle gear. In cases where low gear ratios are employed in the rear axle gear to achieve low economical engine operating speeds or where large rear axle gears with hub reduction are employed, the pinion diameter required makes it difficult to accommodate the rear axle gear, e.g. in conjunction with brake installations, on a rear axle beam between the vehicle's tractive wheels and/or between its chassis frame side members.